Ever since you did me the honour of making me your President it has been fairly inevitable that the subject of today's Address should connect the work of hydrographers with that of navigators. It has also been clear to me that I should not try to emulate too closely the two distinguished men of science who have been my predecessors in office. Their Addresses have contemplated, and given us useful thoughts for, the future; mine will be more easily developed from the standpoint of the user, and will attempt to see how accepted principles and methods are in fact being applied for the navigator's purposes.

Upper winds over the North Atlantic are strong and their circulation is complex; until aircraft speeds are considerably increased, therefore, the choice of a route which will take the maximum advantage of the wind distribution consistent with safety can make a worthwhile contribution to operating economy. This paper describes some of the methods adopted by Trans-Canada Airline on its North Atlantic route to achieve this end.

The problem of navigation in high latitudes is becoming increasingly important as the range of modern aircraft increases and the consequent inevitability of the extension of possible operational theatres to include polar regions becomes apparent. The provision of suitable maps of such areas is therefore a matter requiring attention in the near future, and the adoption of a standard projection together with uniformity of presentation of topographical detail must be regarded as a desirable objective in this connection. The aim of this paper is briefly to review and compare the various projections available and so assess which one is most suitable for the purpose.

The library of the Royal Geographical Society contains a great many early charts and works on navigation which will be of interest to members of the Institute. Mr. Crone, the Society's Librarian and Map Curator, describes some of them in this paper, which deals in the main with publications likely to have been used or referred to by practising navigators. Arrangements can be made for members to inspect works in the Society's collection.

There are two stages in the determination of position from current observations. The observations are first resolved into positional form on the chart and plotted so as to give either a fix or a position line. When more than two position lines are available, some of the information is redundant and a problem exists of determining the most likely fix. In the case of air navigation, the number of position lines seldom exceeds three, and the determination of position in this case has been studied in a previous article.

The procedures of dead reckoning require a number of different steps, amongst which are distance measurement, angle measurement, construction of straight-line tracks, the solution of the vector triangle and the process of multiplication and division. The navigator's plotting and dead reckoning instruments are designed to meet these needs. The ruler serves both as a distance-measuring scale and as a means of drawing a straight line track; the protractor measures angles; the dividers measure distances and the Dalton computer serves both as a method of solving the vector triangle and as a circular slide rule for multiplication and division.

This paper describes a new method for the continuous development of astronomical position lines, relative to a moving D.R. position. At present the method is restricted to observations of the stars, but it might later be extended to other bodies. A basic requirement is a precomputed ‘star lattice’, which here takes the form of a series of graduated intercept curves drawn so as to be always at right angles to curves of constant altitude. The star lattice may be prepared and printed in advance, or may be constructed by the navigator himself, immediately before observation, from the data in the new tables, Sight Reduction Tables for Air Navigation (Vol. i, Selected Stars).

When the maritime history of the eighteenth century is under discussion it is usual to stress the limitations imposed by the inability of navigators to determine their longitude. It is generally assumed that since the advent of the Davis Quadrant or back-staff the latitude could be observed with considerable accuracy, and that with the compass in a wooden hull and with the more accurate graduation of the log-line as shown by Norwood, the dead reckoning should, over short periods of time, be reasonably reliable.

In order to gain first-hand experience of the conditions encountered by the growing number of vessels plying the Hudson Bay route, Mr. R. E. Perry, an engineer of the Decca Radar Company recently made a passage to Port Churchill in the S.S. North Anglia.

During the course of this passage a complete radar log was kept by Mr. Perry. This log is noteworthy not only for the many reports of the radar detection of various types of ice but also for the detail and completeness of the information recorded.

A list of existing and projected shore radar installations to aid merchant shipping was given as an Appendix to Mr. Le Page's paper on the requirements for port radar (Vol. V, p. 295), where unfortunately First Narrows Bridge was described as spanning the Fraser River. In making this correction, Commander Lancaster, the Harbour Master at Vancouver, has sent the following description of the installation, which provides a useful supplement to Mr. Le Page's paper.